作者:张伟

爱可生北京分公司 DBA 团队成员,负责 MySQL 日常问题处理和 DMP 产品维护。喜爱技术和开源数据库,喜爱运动、读书、电影,花草树木。

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pt-query-digest 简介

子曰:“工欲善其事,必先利其器”
善于利用好的性能分析工具可以使运维效率事半功倍。pt-query-digest 属于 Percona Toolkit 工具集中较为常用的工具,用于分析 slow log,可以分析 MySQL 数据库的 binary log 、 general log 日志,同时也可以使用 show processlist 或从 tcpdump 抓取的 MySQL 协议数据来进行分析。

部署  Percona Toolkit 

下载最新版本的  Percona Toolkit 
[root@xxx ~]# wget https://www.percona.com/downloads/percona-toolkit/3.2.1/binary/redhat/7/x86_64/percona-toolkit-3.2.1-1.el7.x86_64.rpm--2020-09-02 06:44:43--  https://www.percona.com/downloads/percona-toolkit/3.2.1/binary/redhat/7/x86_64/percona-toolkit-3.2.1-1.el7.x86_64.rpmResolving www.percona.com (www.percona.com)... 74.121.199.234Connecting to www.percona.com (www.percona.com)|74.121.199.234|:443... connected.HTTP request sent, awaiting response... 200 OKLength: 17397876 (17M) [application/x-redhat-package-manager]Saving to: ‘percona-toolkit-3.2.1-1.el7.x86_64.rpm’
100%[=====================================================================================================================================================>] 17,397,876 68.3KB/s in 2m 37s
2020-09-02 06:47:27 (108 KB/s) - ‘percona-toolkit-3.2.1-1.el7.x86_64.rpm’ saved [17397876/17397876]
[root@xxx ~]# ls | grep percona-toolkit-3.2.1-1.el7.x86_64.rpmpercona-toolkit-3.2.1-1.el7.x86_64.rpm
PT 工具是使用 Perl 语言编写和执行的,所以需要系统中有 Perl 环境。安装相关的依赖包,
[root@xxx ~]# yum install perl-DBI.x86_64[root@xxx ~]# yum install perl-DBD-MySQL.x86_64[root@xxx ~]# yum install perl-IO-Socket-SSL.noarch[root@xxx ~]# yum install perl-Digest-MD5.x86_64[root@xxx ~]# yum install perl-TermReadKey.x86_64
安装 Percona Toolkit 
[root@xxx ~]# rpm -iv percona-toolkit-3.2.1-1.el7.x86_64.rpmwarning: percona-toolkit-3.2.1-1.el7.x86_64.rpm: Header V4 RSA/SHA256 Signature, key ID 8507efa5: NOKEYPreparing packages...percona-toolkit-3.2.1-1.el7.x86_64
[root@xxx ~]# rpm -qa | grep perconapercona-toolkit-3.2.1-1.el7.x86_64

工具目录安装路径:/usr/bin

检查慢日志的相关配置

mysql> show variables like '%slow%';+---------------------------+-------------------------------------+| Variable_name             | Value                               |+---------------------------+-------------------------------------+| log_slow_admin_statements | ON                                  || log_slow_slave_statements | ON                                  || slow_launch_time          | 2                                   || slow_query_log            | ON                                  || slow_query_log_file       | /opt/mysql/data/7777/mysql-slow.log |+---------------------------+-------------------------------------+5 rows in set (0.01 sec)
mysql> show variables like 'long_query_time';+-----------------+----------+| Variable_name | Value |+-----------------+----------+| long_query_time | 1.000000 |+-----------------+----------+1 row in set (0.01 sec)
由于更好测试慢日志文件的输出,此处将慢日志执行时间阈值调小。
mysql>  set global long_query_time=0.001000;Query OK, 0 rows affected (0.00 sec)
mysql> show variables like 'long_query_time';+-----------------+----------+| Variable_name | Value |+-----------------+----------+| long_query_time | 0.001000 |+-----------------+----------+1 row in set (0.00 sec)

pt-query-digest 分析慢日志

[root@xxx 7777]# pt-query-digest   mysql-slow.log
# 3.6s user time, 100ms system time, 32.64M rss, 227.52M vsz# Current date: Wed Sep 2 11:22:34 2020# Hostname: xxx# Files: mysql-slow.log# Overall: 37.46k total, 17 unique, 576.26 QPS, 5.58x concurrency ________# Time range: 2020-09-02T11:21:24 to 2020-09-02T11:22:29# Attribute total min max avg 95% stddev median# ============ ======= ======= ======= ======= ======= ======= =======# Exec time 363s 1ms 183ms 10ms 23ms 8ms 8ms# Lock time 1s 0 34ms 35us 38us 603us 0# Rows sent 182.14k 0 100 4.98 0.99 21.06 0# Rows examine 491.83k 0 1.02k 13.45 97.36 56.85 0# Query size 19.82M 5 511.96k 554.80 72.65 16.25k 5.75
# Profile# Rank Query ID Response time Calls R/Call V/M Ite# ==== ============================= ============== ===== ====== ===== ===# 1 0xFFFCA4D67EA0A788813031B8... 328.2315 90.4% 30520 0.0108 0.01 COMMIT# 2 0xB2249CB854EE3C2AD30AD7E3... 8.0186 2.2% 1208 0.0066 0.01 UPDATE sbtest?# 3 0xE81D0B3DB4FB31BC558CAEF5... 6.6346 1.8% 1639 0.0040 0.01 SELECT sbtest?# 4 0xDDBF88031795EC65EAB8A8A8... 5.5093 1.5% 756 0.0073 0.02 DELETE sbtest?# MISC 0xMISC 14.6011 4.0% 3334 0.0044 0.0 <13 ITEMS>
# Query 1: 1.02k QPS, 10.94x concurrency, ID 0xFFFCA4D67EA0A788813031B8BBC3B329 at byte 26111916# This item is included in the report because it matches --limit.# Scores: V/M = 0.01# Time range: 2020-09-02T11:21:59 to 2020-09-02T11:22:29# Attribute pct total min max avg 95% stddev median# ============ === ======= ======= ======= ======= ======= ======= =======# Count 81 30520# Exec time 90 328s 1ms 129ms 11ms 23ms 8ms 9ms# Lock time 0 0 0 0 0 0 0 0# Rows sent 0 0 0 0 0 0 0 0# Rows examine 0 0 0 0 0 0 0 0# Query size 0 178.83k 6 6 6 6 0 6# String:# Databases test# Hosts 10.186.60.147# Users root# Query_time distribution# 1us# 10us# 100us# 1ms ################################################################# 10ms ############################################################ 100ms ## 1s# 10s+COMMIT\G
# Query 2: 41.66 QPS, 0.28x concurrency, ID 0xB2249CB854EE3C2AD30AD7E3079ABCE7 at byte 24161590# This item is included in the report because it matches --limit.# Scores: V/M = 0.01# Time range: 2020-09-02T11:21:59 to 2020-09-02T11:22:28# Attribute pct total min max avg 95% stddev median# ============ === ======= ======= ======= ======= ======= ======= =======# Count 3 1208# Exec time 2 8s 1ms 115ms 7ms 24ms 9ms 3ms# Lock time 38 518ms 17us 34ms 428us 73us 2ms 36us# Rows sent 0 0 0 0 0 0 0 0# Rows examine 0 1.18k 1 1 1 1 0 1# Query size 0 46.01k 39 39 39 39 0 39# String:# Databases test# Hosts 10.186.60.147# Users root# Query_time distribution# 1us# 10us# 100us# 1ms ################################################################# 10ms ############### 100ms ## 1s# 10s+# Tables# SHOW TABLE STATUS FROM `test` LIKE 'sbtest1'\G# SHOW CREATE TABLE `test`.`sbtest1`\GUPDATE sbtest1 SET k=k+1 WHERE id=50313\G# Converted for EXPLAIN# EXPLAIN /*!50100 PARTITIONS*/select k=k+1 from sbtest1 where id=50313\G
# Query 3: 56.52 QPS, 0.23x concurrency, ID 0xE81D0B3DB4FB31BC558CAEF5F387E929 at byte 22020829# This item is included in the report because it matches --limit.# Scores: V/M = 0.01# Time range: 2020-09-02T11:21:59 to 2020-09-02T11:22:28# Attribute pct total min max avg 95% stddev median# ============ === ======= ======= ======= ======= ======= ======= =======# Count 4 1639# Exec time 1 7s 1ms 61ms 4ms 14ms 5ms 2ms# Lock time 3 45ms 11us 958us 27us 44us 30us 23us# Rows sent 0 1.60k 1 1 1 1 0 1# Rows examine 0 1.60k 1 1 1 1 0 1# Query size 0 57.62k 36 36 36 36 0 36# String:# Databases test# Hosts 10.186.60.147# Users root# Query_time distribution# 1us# 10us# 100us# 1ms ################################################################# 10ms ####### 100ms# 1s# 10s+# Tables# SHOW TABLE STATUS FROM `test` LIKE 'sbtest1'\G# SHOW CREATE TABLE `test`.`sbtest1`\G# EXPLAIN /*!50100 PARTITIONS*/SELECT c FROM sbtest1 WHERE id=61690\G
# Query 4: 26.07 QPS, 0.19x concurrency, ID 0xDDBF88031795EC65EAB8A8A8BEEFF705 at byte 21045172# This item is included in the report because it matches --limit.# Scores: V/M = 0.02# Time range: 2020-09-02T11:21:59 to 2020-09-02T11:22:28# Attribute pct total min max avg 95% stddev median# ============ === ======= ======= ======= ======= ======= ======= =======# Count 2 756# Exec time 1 6s 1ms 104ms 7ms 26ms 10ms 3ms# Lock time 18 252ms 13us 19ms 333us 54us 2ms 26us# Rows sent 0 0 0 0 0 0 0 0# Rows examine 0 756 1 1 1 1 0 1# Query size 0 25.10k 34 34 34 34 0 34# String:# Databases test# Hosts 10.186.60.147# Users root# Query_time distribution# 1us# 10us# 100us# 1ms ################################################################# 10ms ################## 100ms ## 1s# 10s+# Tables# SHOW TABLE STATUS FROM `test` LIKE 'sbtest1'\G# SHOW CREATE TABLE `test`.`sbtest1`\GDELETE FROM sbtest1 WHERE id=50296\G# Converted for EXPLAIN# EXPLAIN /*!50100 PARTITIONS*/select * from sbtest1 WHERE id=50296\G

分析 pt-query-digest 输出结果

第一部分:输出结果的总体信息
# 3.6s user time, 100ms system time, 32.64M rss, 227.52M vsz 说明:执行过程中在用户中所花费的所有时间执行过程中内核空间中所花费的所有时间pt-query-digest进程所分配的内存大小pt-query-digest进程所分配的虚拟内存大小
# Current date: Wed Sep 2 11:22:34 2020 说明:当前日期
# Hostname: xxx说明:执行pt-query-digest的主机名
# Files: mysql-slow.log说明:被分析的文件名
# Overall: 37.46k total, 17 unique, 576.26 QPS, 5.58x concurrency ________说明:语句总数量,唯一语句数量,每秒查询量,查询的并发
# Time range: 2020-09-02T11:21:24 to 2020-09-02T11:22:29说明:执行过程中日志记录的时间范围
# Attribute total min max avg 95% stddev median说明:属性 总计 最小值 最大值 平均值 95% 标准差 中位数# ============ ======= ======= ======= ======= ======= ======= =======
# Exec time 363s 1ms 183ms 10ms 23ms 8ms 8ms说明:执行时间# Lock time 1s 0 34ms 35us 38us 603us 0说明:锁占用时间# Rows sent 182.14k 0 100 4.98 0.99 21.06 0说明:发送到客户端的行数# Rows examine 491.83k 0 1.02k 13.45 97.36 56.85 0说明:扫描的语句行数# Query size 19.82M 5 511.96k 554.80 72.65 16.25k 5.75 说明:查询的字符数

第二部分:输出队列组的统计信息

# Profile说明:简况# Rank Query ID                      Response time  Calls R/Call V/M   Ite# ==== ============================= ============== ===== ====== ===== ===#    1 0xFFFCA4D67EA0A788813031B8... 328.2315 90.4% 30520 0.0108  0.01 COMMIT#    2 0xB2249CB854EE3C2AD30AD7E3...   8.0186  2.2%  1208 0.0066  0.01 UPDATE sbtest?#    3 0xE81D0B3DB4FB31BC558CAEF5...   6.6346  1.8%  1639 0.0040  0.01 SELECT sbtest?#    4 0xDDBF88031795EC65EAB8A8A8...   5.5093  1.5%   756 0.0073  0.02 DELETE sbtest?# MISC 0xMISC                         14.6011  4.0%  3334 0.0044   0.0 <13 ITEMS>

第三部分:输出每列查询的详细信息

# Query 1: 1.02k QPS, 10.94x concurrency, ID 0xFFFCA4D67EA0A788813031B8BBC3B329 at byte 26111916说明:查询队列1:每秒查询量,查询的并发,队列1的ID值,26111916:表示文中偏移量(查看方法在下面‘偏1’中)
# This item is included in the report because it matches --limit.# Scores: V/M = 0.01# Time range: 2020-09-02T11:21:59 to 2020-09-02T11:22:29# Attribute pct total min max avg 95% stddev median# ============ === ======= ======= ======= ======= ======= ======= =======# Count 81 30520# Exec time 90 328s 1ms 129ms 11ms 23ms 8ms 9ms# Lock time 0 0 0 0 0 0 0 0# Rows sent 0 0 0 0 0 0 0 0# Rows examine 0 0 0 0 0 0 0 0# Query size 0 178.83k 6 6 6 6 0 6说明:查询的详细说明,在第一部分/第二部分有相关参数说明# String:# Databases test说明:使用的数据库名称# Hosts 10.186.60.147说明:使用的主机IP# Users root说明:使用的用户名# Query_time distribution# 1us# 10us# 100us# 1ms ################################################################# 10ms ############################################################ 100ms ## 1s# 10s+说明:查询时间分布COMMIT\G说明:执行的慢语句信息# Query 2: 41.66 QPS, 0.28x concurrency, ID 0xB2249CB854EE3C2AD30AD7E3079ABCE7 at byte 24161590# This item is included in the report because it matches --limit.# Scores: V/M = 0.01# Time range: 2020-09-02T11:21:59 to 2020-09-02T11:22:28# Attribute pct total min max avg 95% stddev median# ============ === ======= ======= ======= ======= ======= ======= =======# Count 3 1208# Exec time 2 8s 1ms 115ms 7ms 24ms 9ms 3ms# Lock time 38 518ms 17us 34ms 428us 73us 2ms 36us# Rows sent 0 0 0 0 0 0 0 0# Rows examine 0 1.18k 1 1 1 1 0 1# Query size 0 46.01k 39 39 39 39 0 39# String:# Databases test# Hosts 10.186.60.147# Users root# Query_time distribution# 1us# 10us# 100us# 1ms ################################################################# 10ms ############### 100ms ## 1s# 10s+# Tables# SHOW TABLE STATUS FROM `test` LIKE 'sbtest1'\G# SHOW CREATE TABLE `test`.`sbtest1`\GUPDATE sbtest1 SET k=k+1 WHERE id=50313\G# Converted for EXPLAIN# EXPLAIN /*!50100 PARTITIONS*/select k=k+1 from sbtest1 where id=50313\G
# Query 3: 56.52 QPS, 0.23x concurrency, ID 0xE81D0B3DB4FB31BC558CAEF5F387E929 at byte 22020829# This item is included in the report because it matches --limit.# Scores: V/M = 0.01# Time range: 2020-09-02T11:21:59 to 2020-09-02T11:22:28# Attribute pct total min max avg 95% stddev median# ============ === ======= ======= ======= ======= ======= ======= =======# Count 4 1639# Exec time 1 7s 1ms 61ms 4ms 14ms 5ms 2ms# Lock time 3 45ms 11us 958us 27us 44us 30us 23us# Rows sent 0 1.60k 1 1 1 1 0 1# Rows examine 0 1.60k 1 1 1 1 0 1# Query size 0 57.62k 36 36 36 36 0 36# String:# Databases test# Hosts 10.186.60.147# Users root# Query_time distribution# 1us# 10us# 100us# 1ms ################################################################# 10ms ####### 100ms# 1s# 10s+# Tables# SHOW TABLE STATUS FROM `test` LIKE 'sbtest1'\G# SHOW CREATE TABLE `test`.`sbtest1`\G# EXPLAIN /*!50100 PARTITIONS*/SELECT c FROM sbtest1 WHERE id=61690\G
# Query 4: 26.07 QPS, 0.19x concurrency, ID 0xDDBF88031795EC65EAB8A8A8BEEFF705 at byte 21045172# This item is included in the report because it matches --limit.# Scores: V/M = 0.02# Time range: 2020-09-02T11:21:59 to 2020-09-02T11:22:28# Attribute pct total min max avg 95% stddev median# ============ === ======= ======= ======= ======= ======= ======= =======# Count 2 756# Exec time 1 6s 1ms 104ms 7ms 26ms 10ms 3ms# Lock time 18 252ms 13us 19ms 333us 54us 2ms 26us# Rows sent 0 0 0 0 0 0 0 0# Rows examine 0 756 1 1 1 1 0 1# Query size 0 25.10k 34 34 34 34 0 34# String:# Databases test# Hosts 10.186.60.147# Users root# Query_time distribution# 1us# 10us# 100us# 1ms ################################################################# 10ms ################## 100ms ## 1s# 10s+# Tables# SHOW TABLE STATUS FROM `test` LIKE 'sbtest1'\G# SHOW CREATE TABLE `test`.`sbtest1`\GDELETE FROM sbtest1 WHERE id=50296\G# Converted for EXPLAIN# EXPLAIN /*!50100 PARTITIONS*/select * from sbtest1 WHERE id=50296\G

偏 1:

可以利用偏移量在慢查询日志文件中到查找到具体的 SQL 语句,查找方法如下:
[root@xxx 7777]# tail -c +26111916 ./mysql-slow.log | head# Time: 2020-09-02T11:22:21.062995-00:00# User@Host: root[root] @  [10.186.60.147]  Id:  1177# Query_time: 0.128524  Lock_time: 0.000000 Rows_sent: 0  Rows_examined: 0SET timestamp=1599045741;COMMIT;# Time: 2020-09-02T11:22:21.063202-00:00# User@Host: root[root] @  [10.186.60.147]  Id:  1179# Query_time: 0.126925  Lock_time: 0.000000 Rows_sent: 0  Rows_examined: 0SET timestamp=1599045741;COMMIT;
 在生产环境中根据输出的慢 SQL 详情进行合理的语句调整。

参考文档

  • https://www.percona.com/doc/percona-toolkit/LATEST/pt-query-digest.html
  • https://dev.mysql.com/doc/refman/5.7/en/slow-query-log.html

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